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Aero Guy said…

Interesting post. In the design of race cars there is a lot of good aerodynamics that takes place. Take your typical airfoil shape, flip it upside-down and then span it over a length and you have a simple spoiler (as seen on the front and rear of the car), generating a lift vector towards the ground!! Hence the major ‘suction’ and the huge down force acting on the car. In fact, a lot of research is going on in the aerodynamics of automobiles at the moment. Starting back in the 1970’s and stemming from the concerns over oil, groups like NASA began to look into designing better aerodynamics into consumer vehicles. Better aerodynamics means less drag and therefore better gas mileage, which is something that we can never have too much of. NASA has recently done a lot of work on the aerodynamics of large tractor-trailers. With as many tractor-trailers that cruise the interstates here in the U.S., there could be huge saving in many trucking company’s pocket books with better gas mileage, and even better news for the environment, with lower consumption of gasoline. See the following:

This is a tractor-trailer that was put in NASA’s 80x120ft wind tunnel at Ames Research Center. Their goal was to reduce the drag the Semi saw and determine what those reductions might do to gas mileage. You can see the side panels that were installed on the trailer. These help to prevent the air streams from going around the cab and then coming back together before they hit the back wheels (that is what happens in that large void under the trailer). If they do come back together before hitting the back wheels, there are huge drag effects as that powerful air slams into the rear wheels and has no place to go. Also, the panels that are on the rear of the trailer act to smooth the flow as it comes off of the back of the truck to prevent a large drag bucket from forming behind the trailer, which also causes large drag contributions. From what I have heard, these simple modifications could save millions of dollars in gas mileage, and who knows what the results might be for the environment. You can probably expect to see company’s like Wal-Mart to start using such technologies on their trucks, not only to save money, but also to save the environment.

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